Staff Report on the Four Flights and Civil Aviation Security, National Commission on Terrorist Attacks Upon the United States, declassified February 10, 2005 [finding that the FAA had at least 52 warnings and intelligence on al-Qaeda between April and September 11, 2001, but none were specific enough to invoke specific security precautions]. Read the full text of the Report here [PDF]. Reported in JURIST's Paper Chase here.